Mass Measurement System Using Relay Feedback with Hysteresis
01 Jan 2008-Journal of System Design and Dynamics (The Japan Society of Mechanical Engineers)-Vol. 2, Iss: 1, pp 188-196
TL;DR: In this paper, the effects of system parameters and disturbances on measurement accuracy were examined experimentally using an on-off relay with hysteresis and switches force acting on the object in relation to its velocity.
Abstract: Mass measurement using a relay feedback system was studied experimentally. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle in the feedback system. The mass of the object is determined from the period of this limit cycle. The apparatus manufactured for experimental study uses two voice coil motors (VCM's), one of which is for driving the object and the other is for generating prescribed disturbances. The effects of system parameters and disturbances on measurement accuracy were examined experimentally.
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TL;DR: In this article, a two-inertia motor bench with gear coupling was used to detect the presence and extent of the backlash in two-mass actuated systems, with a low backlash gap of about one degree.
Abstract: Backlash, also known as mechanical play, is a piecewise differentiable nonlinearity which exists in several actuated systems, comprising, e.g., rack-and-pinion drives, shaft couplings, toothed gears, and other elements. Generally, the backlash is nested between the moving elements of a complex dynamic system, which handicaps its proper detection and identification. A classical example is the two-mass system which can approximate numerous mechanisms connected by a shaft (or link) with relatively high stiffness and backlash in series. Information about the presence and extent of the backlash is seldom exactly known and is rather conditional upon factors such as wear, fatigue and incipient failures in components. This paper proposes a novel backlash identification method using one-side sensing of a twomass system. The method is based on the delayed relay operator in feedback that allows stable and controllable limit cycles to be induced, operating within the unknown backlash gap. The system model, with structural transformations required for the one-side backlash measurements, is given, along with the analysis of the delayed relay in velocity feedback. Experimental evaluations are shown for a two-inertia motor bench with gear coupling, with a low backlash gap of about one degree.
10 citations
TL;DR: This brief tutorial paper is summarizing the basic principles of relay feedback systems, discuss several characteristics interesting for applications, and address some perspectives of further use for the system identification.
Abstract: Relay feedback systems belong, since long, to rather classical topics of the control theory and engineering. While they were first used as robust and simple switching elements in the automatic control, over time, they experienced different periods of renewed interest regarding both the theoretical analysis and applications. Examples here are the automatic tuning of the simple feedback controllers, delta-sigma modulators for analog-digital converters, robust relaybased controls, nonlinear systems analysis and identification, and others. One of the remarkable features when using relays in feedback is appearance of the stable limit cycles. The structural and parametric conditions for the stable limit cycles, their prediction, and controllability of magnitude and frequency already found answers, to the large part, in the former research, driven by both theoretical curiosity and application requirements. This brief tutorial paper is summarizing the basic principles of relay feedback systems, discuss several characteristics interesting for applications, and address some perspectives of further use for the system identification. A case-specific study of estimating the unknown backlash, hidden within two-mass systems, is demonstrated along with experimental example, based on provoking the controllable drifting limit cycles by the non-ideal relay in the velocity feedback loop.
8 citations
TL;DR: Although inception of the measurement of astronaut body mass measurement was as old as Skylab era, progress in the field has not been as expected as mentioned in this paper, there are fundamental physical difficulties as well as program management issues.
Abstract: Although inception of the measurement of astronaut body mass measurement was as old as Skylab era, progress in the field has not been as expected. There are fundamental physical difficulties as well as program management issues. New mass measurement systems with the current sensor technologies should be prepared, and the new sensor system could be expanded for “Drop Tower” in space.
6 citations
Cites methods from "Mass Measurement System Using Relay..."
...Extensive data analysis was tried [13, 14], but only one run data were recovered....
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TL;DR: A review of mass measurement devices developed by the author is presented in this paper, where the treated devices are classified into two types: the first type uses a dynamic vibration absorber as a device for both mass measurement and vibration control.
Abstract: A review of mass measurement devices developed by the author is presented. According to the measurement principles, the treated devices are classified into two types. The first type uses a dynamic vibration absorber as a device for both mass measurement and vibration control. The main advantage is no vibration transmitted into the surrounding structures during measurement. The second type uses relay feedback. The advantages are simpler mechanism and robustness against disturbances. In this article, the principles of measurement of each type are presented.
6 citations
01 Jan 2017
TL;DR: In this paper, the effect of the delay on mass estimation was investigated experimentally and analytically, and an estimating equation including this effect was derived, which supports the validity of the derived estimating equation.
Abstract: Abstract This paper treats a relay-feedback mass measurement system that uses a relay with hysteresis and feeds back the velocity of the object. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle. The mass of the object is determined from the period of this cycle. In previous study, the actual trajectory of the limit cycle was different in shape from the theoretical one so that the prerequisites of the estimation formula were not satisfied. The delay of the velocity sensor is a main factor of such degradation. In this paper, the effect of the delay on mass estimation is investigated experimentally and analytically. In addition, an estimating equation including this effect is derived. Experimental result supports the validity of the derived estimating equation.
4 citations
Additional excerpts
...実 験 3・1 実験装置 前述したようにこれまでの研究では板ばねにより測定対象物を支持していたが，この板ばねの剛性が測定結果 に影響を与えることが明らかとなった(Mizuno et al., 2008)．したがって，著者らはよりシンプルな系で測定を行う ために空気軸受によって被測定物を支持した装置を製作した．装置の概要を図 3に示す．被測定物の軸受に空気 軸受を使用することで，振動系に生じる摩擦力を極めて小さくできる．また，これを三つ使用することで並進一 自由度に拘束している．アクチュエータにはボイスコイルモータ (Voice Coil Motor : VCM)…...
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...実 験 3・1 実験装置 前述したようにこれまでの研究では板ばねにより測定対象物を支持していたが,この板ばねの剛性が測定結果 に影響を与えることが明らかとなった(Mizuno et al., 2008)....
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...そこで著者らは,外乱の影 響を受けにくく,かつ比較的簡単な機構で正確な測定を行える測定を行える装置の実現を目指して, (7)速度フィードバック系を利用した測定方法(水野,八百坂,2002)(Mizuno et al., 2008) を提案している....
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...また,これまでの研究ではドリフトを防止するため板ばねにより測定対象物を支持していたが,この板ばねの 剛性が測定結果に影響を与えることが明らかとなった(Mizuno et al., 2008)....
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...…et al., 1997) （4）被測定物を回転させ，そのときの遠心力から質量を推定する方式(前田他，1993) （5）動吸振器を利用した方式(水野，根岸，1999) （5.a）測定対象物を回転させる方式(水野，荒木，1996) （5.b）測定対象物を振動させる方式(水野他，2002) E-mail of corresponding author:…...
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References
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TL;DR: It is shown that FCM is an accurate and more desirable mass-measurement method under weightless conditions through the results of the experiment.
34 citations
TL;DR: The estimates of accuracy of mass measurement by this device are given, and the results of measuring the masses of cosmonauts' bodies on the Salyut 5 and 6 orbital stations are presented.
24 citations
18 citations
TL;DR: In this article, a new type of mass-measurement system under weightless conditions is proposed which uses a dynamic vibration absorber as a measuring device, where an object to be measured is fixed to a rotating table (rotor) at a distance from the rotation axis.
Abstract: A new type of mass-measurement system under weightless conditions is proposed which uses a dynamic vibration absorber as a measuring device. In this system, an object to be measured is fixed to a rotating table (rotor) at a distance from the rotation axis. Since it makes the rotor unbalanced, a centrifugal force whose amplitude is proportional to the mass is generated during rotation. It works as a harmonic excitation and forces a structure supporting the table to vibrate. However, a dynamic vibration absorber attached to the structure is tuned or controlled to reduce the vibration to zero. When the structure does not move at all, the absorber mass vibrates in such a way that the product of the mass and the displacement amplitude is equal to the amount of unbalance, that is, the product of the mass to be measured and its distance from the rotation axis. Therefore, the mass of the object is determined by measuring the displacement amplitude of the absorber mass. In this study, the principles and features of the proposed mass-measurement system are clarified. Experiments are carried out with a developed apparatus having an active dynamic vibration absorber. This apparatus can perform measurement at various rotational speeds because the absorber’s natural frequency can be tuned by a feedback parameter. Experimental results demonstrate the feasibility of the proposed mass-measurement system.
15 citations